Exhaust systems often include mufflers or silencers to reduce undesirable noise generated by the exhaust system. Silencers typically include an outer housing through which an exhaust pipe extends from an inlet to an outlet. Acoustic material, such as fiberglass for example, can surround the exhaust pipe and fill an interior cavity of the outer housing to provide desired noise reduction. Optionally, the exhaust pipe can be formed to include perforations in fluid communication with the interior cavity of the outer housing to provide the desired noise reduction.
The exhaust pipes are subjected to high exhaust gas temperatures. In order to provide a weight savings, the outer housing of the silencers can be made from composite materials; however, under certain operating conditions the exhaust gas temperatures may exceed the melting temperature of the composite outer housing. One proposed solution has been to use a thermal isolation disc at the connection interface between the outer housing and the exhaust pipe. Current thermal isolation discs use distance from the heat source to keep the temperature at the interface between the composite material and steel material of the exhaust pipe below the material limits of the composite material. This is done by increasing an outer diameter of the disc until the distance between an inner diameter and the outer diameter is sufficient such that heat at the outer diameter is below the composite material limit. Optionally, an axially extending, cone-shaped disc has been used to connect the exhaust pipe to the outer housing. Both of these configuration are disadvantageous due to the need for larger areas or lengths to accommodate the enlarged diameter or the length of the cone.